Growing Bananas in the Desert Posted on February 23rd, 2010
GOING BANANAS IN PHOENIX
Banana trees, although sparsely populated, are growing in
practically every section of Phoenix and surrounding areas.
Their broad leaves peeking over back fences and adorning
sheltered enclaves in front yards are not hard to find.
Although these are mostly unknown, or unnamed, varieties,
it can be accurately assumed for the purpose of this
discussion, that many of their titled cousins of the kind
sold at supermarkets will flourish here quite as well.
Temperatures over 100 and an occasional frost can take a
toll but with a little luck and a bit of acquired know-how,
you can enjoy beautiful, tropical foliage growing next to a
saguaro cactus and later treat yourself to a banana split
made with a homegrown banana.
The banana, by the way, is not a tree but an herb. Julian
W. Sauls, Extension Horticulturist with the Texas A&M
University Agricultural Extension Service describes it as a
tropical, herbaceous plant consisting of an underground
corm and a trunk (pseudostem) comprised of concentric
layers of leaf sheaths. A true stem with a terminal
inflorescence (flower) that bears fruit is the last thing
to emerge from the center. The flowers appear in groups
called hands along the stem and are covered by purplish
bracts that roll back and shed as the fruit stem develops.
Generally, a bract rolls up and sheds to expose a new hand
of flowers almost daily.
A single banana pseudostem will live for only two to three
years or until its fruit is harvested and the stem cut
down. But, the corm from which it grew can survive for many
years and every one of the dozens of pups it produces has
the potential for a stalk of bananas. The corm will
continue to enlarge and store energy to nurture an endless
supply of pups.
You should grow your banana in full sun even in the summer.
If, however, you expose a young, tender plant recently
severed from the mother corm to that environment, it will
probably fry because it has no roots. New shoots arise from
underground buds in an established corm. They receive
nourishment during their first few months of existence from
the corm while shaded by the foliage of the other members
growing from that same mat. After being rudely severed from
its mother and planted with its few roots cut off, you must
act as a surrogate and provide shelter and water until it
can grow new roots, adapt to the new environment and
eventually build a colony of its own.
Strong winds shred the leaves of bananas but the green
tatters will still take part in photosynthesis and
manufacture food. Keep an individual leaf attached until
two/thirds of it has turned brown. The unattractive dead
leaves needn’t be removed, either, but if, for cosmetic
purposes, they are, you can shred or chop them up and layer
the debris around the base for mulch.
A single banana pseudostem has a short life span producing
one stalk of bananas in about 18 months in ideal soil and
climate. With less than a perfect environment, you may wait
for 2 years or longer to sink your teeth into your own,
homegrown, tree-ripened banana. One plant will multiply
into a grove in two or three years, however, and will need
restraining to remain attractive.
The banana needs well-drained rich, organic soil and, in
warm weather, lots of water. During winter after the
morning temperature drops to about 55 degrees Fahrenheit,
growth virtually shuts down and very little moisture is
required to sustain the plant. The soil around it should be
damp. Irrigate only enough to keep it that way. When
thirsty, the leaves tend to fold together to conserve
moisture. Study them and learn their sign language.
Before planting your banana, test the soil’s ability to
drain. Dig a post-size hole about 2 feet deep. Fill it with
water. If it empties within two hours, the drainage is
ideal. If you continue to refill that same hole, however,
you may reach a point when the water remains for a long,
long time. If you irrigate the banana to that extent after
it has been put in the ground, the roots won’t get air and
rot will set in. Learn to adjust the irrigation frequency
to the rate at which the water permeates through and out of
the root zone with a flushing action. Wet-feet can kill
bananas any time of the year but winter is a most crucial
period when water should not be added until the soil is
quite dry. This herb is susceptible to diseases associated
with cool, wet, soggy soil. Of the numerous other diseases
that tend to plague the banana in the tropics, this desert
climate does not appear to harbor them.
Banana feeder roots can reach as far away from the pseudo
stem as the tips of the leaves extend outward. If at all
possible, deep water and feed to and just beyond that
range. A common tendency is to irrigate in a basin tightly
encircling the corm. Under those conditions, the plant
usually languishes under malnutrition. Roots will not
penetrate into dry soil and a restricted root system will
retard every other feature of the banana plant.
Bananas frequently bloom in Phoenix but fruit is often
stunted and limited to three or four hands with rather
bland flavor. That can be a function of genetics but poor
fruit quality is more likely the result of nutrient
deficiency and inadequate water. Tasty fruit can be
produced here. Quality may also suffer when the flowering
stem is engulfed in a dense banana grove or in close
proximity to other hungry, thirsty vegetation. Fruiting
exacts a large energy toll from the corm requiring a lot of
food and water to sustain it. Competition for the available
nutrients is not helpful. Fertilizers high in potassium(K)
are often recommended and are evidently a part of a healthy
banana’s diet.
After a stalk of bananas has developed, it may be 5 to 7
months before the fruit is mature and ready to pick. If the
stalk is exposed to direct summer sun, cover it loosely
with any reflective lightweight material; an old T-shirt
perhaps. Cut the stalk at the yoke when the ribs on the
bananas have practically disappeared and have the
appearance of a supermarket banana. Hang it in a dark,
sheltered spot to ripen or leave it protected on the plant.
Pick a “hand” at a time as desired to ripen on the kitchen
counter like any other banana.
In nature, there is no such thing as a “banana plant”.
Multiple stems emerge from a corm that continually enlarges
and sends up new shoots. With adequate food and water,
there will always be a “herd” ranging in size from big ones
to tiny suckers popping through the surface. To get the
best and most fruit, especially under less than ideal
conditions, keep the population of any group to three,
staggered in size. One adult that will be chopped down to a
two-foot stub after the stalk of bananas is harvested; one
juvenile and a baby are all you need. Remove all other
growth. Sever suckers at their base soon after emergence
and scoop out a hollow with a spoon. Fill the cavity with
an equal amount of kerosene to kill the bud that will
otherwise continue to grow and consume energy. After the
inflorescense has emerged, lop off the flower head as soon
as the hands fail to set; the immature, tiny fruits fall
off. Bananas are believed to flower only after a certain
number of leaves have been produced. Guesstimates run to
sixty. But, the number of months it takes to reach the
magic number depends upon the plant’s immediate
environment. Count them with a permanent marker if you
really wish to satisfy your curiosity.
An old compost pit would be the perfect spot to plant a
banana, it is often said. But, you would still have to
fertilize the plant if it is your good fortune to have one
in your yard. Bananas can be foliar fed weekly with a
balanced, soluble fertilizer. Apply by drenching the leaves
on both sides during a cool part of the day. Frequent light
feeding of these herbs only when actively growing is better
than sporadic, heavy doses of nitrogen that is quickly
leached away.
During the active growing season, apply 1/4th cup of
ammonium sulfate every two weeks on non-fruiting plant
groups and 1/4th cup weekly on fruiting plants. Blend the
dry fertilizer into damp soil in a shallow trench at least
18 inches from the clump and water it in until a probe can
be easily inserted 18 inches into the ground. Do not
fertilize bananas when the morning temperature drops below
55 degrees. In cold weather, growth has virtually shut down
and they cannot use the additional nutrient.
To harvest suckers, sever them vertically all the way
around the stem. Use a sharp, clean 12’ to 15’ narrow
shovel to its full depth. Worry the base out while
inflicting as little trauma as possible. If the sucker has
no roots, it probably won’t survive. Cut off any existing
roots and let the wounds scab off in full shade for several
days before planting at the same depth. When you dig the
pup(sucker), remove all its leaves as well at their point
of emergence from the stem. When you plant the corm, keep
its soil on the dry or slightly damp side until active new
growth of at least one new leaf appears from its center.
The average mild, Phoenix frost of moderate duration will
never kill the corm and roots but the tender leaves will
freeze readily unless they can be covered or otherwise
protected. The length of the freeze is often forecast. That
information is critical to determine the extent of
protection you put in place. One hour at 32F may inflict
minor injury. Three hours at 33F could kill every tender
thing in your yard.
Depending upon the frost severity expected, one or all of
the following protective measures can be used if the plants
are too tall to be simply covered with a sheet or frost
cloth. First, remove any heavy mulch from the basin until
you need it again to preserve moisture. Plug in an air fan
and direct the air into the leaves. Use one with the
largest volume output you can find. An industrial
oscillating fan on a stand works great. To protect the
stems, wrap them with old jackets or blankets and drape
Christmas tree lights on the leaves. Put a floodlight or
other heat source underneath. The shock suffered from
losing its foliage will delay fruiting and set the
development of a banana back several weeks making the
energy you spend saving it a worthwhile effort.
Another strategy to cope with a severe frost warning is to
remove all leaves and wrap the stem and top with much
greater ease. If hit unexpectedly with a frost that kills
all the leaves, let them hang for additional protection
until frost danger is past.
Assume that this winter will bring a severe freeze and
prepare for it in advance. Use electrical devises with
caution.
In summary, grow bananas in full sun in well-drained soil
rich in organic material. Water and feed them well during
warm weather, let the plants rest during the winter,
protect them from the two or three mild frosts and mount a
sign in your front yard. TROPICAL FRUIT GROWN HERE.
Compiled by Dick Gross, Founder of Arizona Rare Fruit Growers
